Humidity contbol



A. E.- KRICK.

HUMIDITY CONTROL.

APPLICATION FILED JAN-10.1919.

Patented Sept. 9, 1919.

awwvvm FFICE.

ARTHUR E. KRICK, OF INDIANAPOLIS, INDIANA, ASSIGNOR, BY DIRECT AND MESNE ASSIGNMENTS, TO THE HUMIDITY CONTROL COMPANY, OF INDIANAPOLIS, IN-

DIANA, A CORPORATION OF INDIANA.

HUMIDITY common.

isiasiv.

Specification of Letters Patent.

Patented Sept. a, 1919.,

Application filed January 10, 1919. Serial No. 270,523.

To all whom it may concern:

Be it known that I, ARTHUR E. KnIoK, a citizen of the .United States, residing at Indianapolis, in the county of Marion and State of Indiana, have invented a new anduseful Humidity Control, of which the following is a specification.

It is the object of my invention to control automatically the wet-bulb and dry-bulb temperatures of a dry kiln or other inclosed space, so that the dry-bulb temperature and the difference between the dry-bulb and wetbulb temperatures may be automatically maintained, and so that in case the dry-bulb temperature does vary the wet-bulb temperature will follow it so as to maintain substantially constant the difference between such two temperatures and so maintain the rela tive humidity suliiciently nearly constant for any usual variations in temperature.

In attaining this result, I automatically control the heat supplied to the kiln or inclosure by a dry-bulb thermostat, which acts on a regulating device (such as a steam valve) to vary the heat supplied in accordance with the temperature of the kiln or inclosure; and I automatically control the amount of moisture taken up by the air in the kiln or inclosure by a wet-bulb thermostat and a dry-bulb thermostat which act in opposition on a regulating device (such as a steam valve controlling the temperature of water in a water pan in the kiln or inclosme) to vary the amount of moisture which is taken up by such air. first regulating device, any desired temperature may be maintained; and by adjustment of the second regulating device, with relation to the adjustment of the first, any-desired difference between the wet-bulb and dry-bulb temperatures may be obtained, the wet-bulb and dry-bulb thermostats which act on said second regulating devicetending to operate it to decrease and increase respec tively the amount of moisture-taken up by the air so that the difference between the wet-bulb and dry-bulb temperature may be maintained constant even though for any reason the dry-bulb temperature as regulated by the first regulating device departs from the desired constant value. c r

The accompanying drawing illustrates my invention.

Figure 1 is a vertical section through a a By adjustment of the kiln embodying my invention, showing the control mechanlsm rather dlagrammatically;

Fig. 2 is an enlarged view of the humidification steam valve and its operating mechanism and Fi 3 is a fra mentar view showing a modified arrangement whereby the twothermostats 10 and 42 are combined.

The drying chamber 10 of the kiln has low the coils 13 are water troughs 15, in,

which a constant water level is maintained by float valves 16 controlling the water supplied from any suitable source through pipes 17. Between the two water troughs 15 is an air duct 18, leading from the atmosphere and opening into the space directly above the water in the troughs 15 by suitable apertures 19, so as. to supply fresh air. Suitable baflies 20 are provided, for directing the flow of air upward from above the water trough 15 to the air-heating coils 13,

whence the air passes through the drying chamber 10 and down between the side walls these chimneys being controlled by dampers 22, preferably located in the walls 11 near the vertical bafiles 20, some above and some below the .upper edges of such vertical baffles. By adjustingthe dampers 22 the amount of air which escapes through the chimneys 21 and the corresponding amount of fresh air which is drawn in through the air duct 18 and the apertures 19 are controlled. Steam coils 23 are immersed in the water in the water troughs 15, forheating such water to promote the evaporation thereof into the air which passes thereover; the amount of such evaporation depending upon the temperature to which the water is heated. Thus the air is heated by, the steam coils 13, which set up the air circulation; and the air is humidified by passing over the water troughs 15, the amount of humidification depending upon the temperature of the water in such troughs.

In order to control automatically-theory bulb' and wet-bulb temperatures of the air I within the drying chamber 10, and the difference between such temperatu e re? the air, the steam supply to the coils 13 is and suitable sh'ut-ofi valves and, if neces-v sary, pressure-reducing valves. The pressure-operated valves '25. and 26 are of any suitable type. The valve is shovyn (only diagrammatically) as having a pressure chamber the movable member of which is connected to the valve stem and tends to close the valve, acting in op osition to a lever 29 on which is an: adjusta le weight 30 which tends to open the valve and by the ad- I justmento'f which the temperature at which the valve operates may "be controlled.' The valve'ee, of which theo'perating mechanism is shown in detail in. Fig. 2, has a threaded valvestem31, whichf'is connected by a pin .and slot connection to one end of a lever 32 hung on alink '33, the valve stem being 30.

provided with suitable adjusting nuts for adjusting its relation to such lever; and the 1 other end of the levera32 projects through a a slot in a member 34, whichhas adjustable connectionsto the movable members of two pressurechambers 35 and 36, which act in opposition on such lever 32 and through it on thevalveste 31, the pressure in the upper chamber 3 tending to close the valve 26 and that in the lower chamber 36 tending to open such valve. The pressure chamber 4 28 of the. valve 25 and the pressure chambers 35. and 36 of the valve 26 are respectively connected bysuitable tubes 37, 38,

' and 39 to three thermostatic elements 40, 41,

and 42 located within the drying chamber 10 soasto be responsive to the air condi- 40- and .42 are dry-bulb elements, so that they are both responsive-"toithe dry-bulb temperature of the air insuch drying chamber; in consequence, though for simpligalty' these two thermostatic elements 40 and 42 covered by a fabric or wicking 43 which dips into the water in a water tank 44 in which a constant water level is maintained by a float valve 45 controlling the supply ofwater to. suchtank from any suitable source through a supply plpe 46; so that such thermostatic element 41 is responsive tothe upon how far the relative humidit air inthe-drying chamber 10 is below 100%,

' y- Of & pressure-operated valve 25 H g ;.the diiference between the wet-bulb and and that to the coils 23 is by way of a. similar pressure-operated valve 26; the steam supply comes from any suitable. source, which may be a common source for both coils, by way of a steam pipe 27 varies upon change in temperature. *change 1n pressure is transmitted to the refibers 35 and 36 and with res trons therein. The thermostatic elements wet-bulb temperature of the air in the dryis less-than the dry-bulb temperature (to (which the thermostatic elements 40 and 42 sponse to variations in these conditions ofv chamber, which wet-bulb temperature are responsive) by an amount d pending of the dry-bulb temperatures being zero when the relative humidity is 100%, all in accordance with the well-understood laws of psychrometry. The thermostatic elements 40, 41, and 42 are illustrated as of the fluidcontaining type, in which the'fluid pressure spectlve chambers 28, 35, and 36 of the associated steam valves, to produce closing of. the valve 25' and opening of the valve 26 upon rise inthe dry-bulb temperature and consequent increase of pressure in the cham- This bars 28 and 36, and closing of the .valve 26 upon rise in the wet-bulb temperature and consequent increase of pressure in the chamber 35 and vice versa. I

In operation, the weight 30 of the valve 25 is set to produce a closing movement of such valve when the dry-bulb temperature of the air in the drying chamber 10 exceeds the. desired value, and an. opening movement of such valve when such drybulb temperature falls below that desired value. The steam supplied through the valve 25 to the coils 13 heats the .air in the drying chamber 10 and produces circulation of suchair; and the dry-bulb temperature of such air in the chamber 10 is maintained constant, within the limits of sensitiveness of the valve 25 in its closing and opening movements as produced by the thermostat 40 upon the rise and fall of such dry-bulb temperature above and below the desired value.

The setting of the lever 32 with relation to the two movable members of the cham stem 31 depends on. the desired relative humidity-or' rather on the desired diflerence between the wet-bulb and dry-bulb temperatures. This setting is obtained by the lock nuts associated with said valve "stem and .greaterheating of the water in the Water troughs '15, and more evaporation therefrom,'and consequently raises the wet-bulb temperature of the air-1n the chamber 10.

ct to the valve 4 with such movable members, and determines' This in turn acts through "the wet-bulb thermostat $1 to cause the pressure chamber to expand and to overcomev the action of the pressure chamber 36 on the lever 32, and thus to produce a closing of the humidification valve 20 to shut oil the supply of steam to the coils 23; this shutting off of the supply of steam occurs when the wet-bulb temperature has risen until the difference between it and the dry-bulb temperature has fa'llento the desired value. Upon a fall in the dry-bulb temperature of the air in the chamber 10, the reverse action takes place. Upon a variation in the wet bulb temperature alone, without any change in the dry-bulb temperature, the variation in its efi'ect on the pressure chamber produces a closing of the humidification valve 26 and a cutting down of the supply of steam to the coils 23 when the wet-bulb temperature rises and an opening of such valve and an increase of the supply of steam to such coils when the wet-bulb temperature t'alls. In other words, changes in the dry-bulb temperature of the air produce corresponding changes in the amount of steam supplied through the humidification valve 26, while changes in the wet-bulb temperature of the air produce inverse changes in the amount of steam supplied through such valve; and

- between these things, changes in the difference between the dry-bulb and wet-bulb temperatures produce corresponding changes in the amount of steam supplied through such valve, so as to maintain such difference substantially constant. The wet-bulb temperature follows the dry-bulb temperature; at a substantially constant d-ifl'crence therefrom.

In consequence, if for any reason the drybulb temperature within the chamber 10 should depart from its desired constant value, as by failure of the valve to .function properly, there will be no great variation 1n the relative humidity of the air in such chamber, and substantially no difference (within the limits of theapparatus) in the difference between the dry-bulb and wetbulb temperatures. Thus, if the valve 25 should'be opened unduly, so as to raise the dry-bulb temperature within the chamber 10, the wet-bulb temperature will rise coy respondingly. and the disastrous effects on the material within the kiln which might follow a sudden drop in the relative humidity of the air in the drying chamber are avoided. By maintaining substantially constant the difference between the dry-bulb and wetbulb temperatures, a rise in the dry-bulb temperature produces an actual rise in the relative humidity of the air instead of a fall therein, which rise is relatively slight if such difference is small but increases as such difference inrreases; as is readily seen from midity of the air as the temperature rises, should a use 111 temperature occur accidentally, there is an actual cutting down of the water-removing drying in spite of the higher 7 temperature, and the bad results which follow too rapid drying are avoided.

Thus by this arrangement ot' control for the valves 25 and 26, the desired dry-bulb temperature and the desired difference between the dry-bulb and wet-bulb temperatures are automatically maintained; and if byaccident there should be an undue variation in the dry-bulb temperature, the wetbulb temperature follows the dry-bulb temperature to maintain the difference substantially constant. The dry-bulb temperature and the difference between the wet-bulb and dry-bulb temperatures may be set for any- .heating coils for heating the water in said vessel, dry-bulb and wet-bulb thermostats responsive to conditions within said drying chamber, means controlled by a dry-bulb thermostat for controlling the supply of heating fluid to said air-heating coils, and means operated jointly by pressures developed by a dry-bulb thermostat anda wetbull) thermostat acting in opposition for controlling the supply of heating'fiuid to said water-heating coils.

'2. A dry-kiln, comprising a drying chamber. air-heating coils. a water vessel, \vater-hcating coils for heating the water in said vessel, dry-bulb and wet-bulb thermostats responsive to conditions within said drying chamber, means controlled by a drybulbthermostat for controlling the supply of' heating fluid to said air-heating coils, and means operated jointly by pressure. developed by a dry-bulb thermostat and a wet-bulb thermostat for controlling the supply ofheating fluid to said water-heating COllS.

3. A drykiln, comprising a drying chamber,*means for heating said drying chamber, means for humidit'ying the air within said drying chamber, dry-bulb and wet-bulb ther-- mostats responsible to the dry-bulb and the wet-bulb temperature of said drying chamber means controlled by a dry-bulb thermostat for controlling said heating means, and means operated jointlv by pressures developed by a dry-bulb thermostat anda wetbulb thermostat acting in opposition for controlling the humidifying eflect of said humidifying means. T v e l 4. A dry-kiln, comprising adrying cham ber, means for heating said drymgchamber, means for humidifying the air withinvsaid drying chamber, dry-bulb and wet-bulb thermostats responsive .to the dry bnlband the Wet-bulb temperature' of saiddrying chamber,; means-controlled by a dry bulb thermostat for controlling said heating means, andmeans operated jointly, by :pressures developed by a "dry-bulb thermostat and a wet-bulb thermostatwforcontrolling the humidifying efiect of said humidifying 1 means;

I 5. Adry-ki1n,comprising a drying chamber, air-heating coils, awater vessel, means forheating l.the waterinsaid vessel, dry- 'bul-b'and wet-bulb thermostats responsive toconditions within said drying chamber,

I, a controlled by a dry-bulb thermostat for controlling 'the supply of heating fluid said ztir-heatingacoils, and means oper- .ated jointly by pressures developed by a drybulb thermostat and a wet-bulb thermostat acting in. opposition for controlling the heating efiect ofsaid Water-heating means.

6. A dry-kiln, comprising a drying chamber, air heating coils, a water vessel, means for-heating the Water in said vessel, drybulb and wet-bulb thern'iostats responsive to conditions ithin said drying chamber, means controlled by a dry-bulb thermostat for controlling the supply of heating fluid to said air-heating coils, and means operated jointly by pressures developed by a dry bulb thermostat and a wet-bulb thermostat for controlling the heating efiect of said water-heating means.

7. A dry-kiln, comprising a drying chamber, means for heating said drying chamber,

a-water vessel, means for heating the water in said vessel, dry-bulb and Wet-bulb thermostats responsive to the dry-bulb and the Wet-bulb temperature of said drying chamber, meansfcontrolled by a dry-bulb thermostat for controlling said heating means, and means operated jointly by pressures developed by a dry-bulb thermostat and a wetbulb thermostat acting in oppostion for controlling the heating effect of said Waterheating means. I

8. A dry-kiln, comprising a'drying chamber, means-for heating said drying chamber, a Water vessel, means for heating the water in said vessel dry-bulb and wet-bulb thermostats responsive tothe dry-bulb and the wetbulb temperature of said drying chamber, a

means controlled by a dry-bulb thermostat 1 for controlling said heating means, and

means operated jointly by pressures developed by a dry-bulb thermostat and a Wetbulb' th rmostat for controlling the heatin effect of said water-heating means,

9. A dry-kiln, comprising a drying cham- \ber, airheating coils, a water vessel, wate rheating coils for heating the water in sald vessel, "dry-bulb and wet-bulb thermostats responsive to conditions within said drying chamber, means controlled by a dry-bulb thermostat for controlling the sup ly of heating fluid to said air-heatin 001 s, and two devices controlled respective y by a drybulb thermostat and a Wet-bulb thermostat and tending respectively to increase and to decreasethe supply of heating fluid to said Water-heating coils.

'efl'ect of said humidifying means.

11. A dry-kiln, comprising a drying chamber, air-heatin coils, a water vessel, means for heating t e Water in said vessel, dry-bulb and wet-bulb thermostats responsive to conditions within said drying chamber, means controlled by a dry-bulb thermostat for controlling the supply of heating fluid to said air-heating coils, and vtwo devices controlled respectively by a dry-bulb thermostat and a wet-bulb thermostat and tending respectively to increase and to decrease the heating efl'ect of said water-heating means.

12. A dry-kiln, comprising a drying chamber, means for heating said drying chamber, a water vessel, means for heating the water in said vessel, dry-bulb and wetbulb thermostats responsive tothe dry-bulb and the wet-bulb temperature of said drying chamber, means controlled by a dry-bulb thermostat for controlling said heating means, and two devices controlled respec-' .tively by a dry-bulb thermostat and a wetbulb thermostat and tending respectively to increase and to decrease the heating effect of said Water-heating means.

13. In combination, air-heating means, air-humidifying means, said air-heating and said air-humidifying means being arranged to act on a common body of air, dry-bulb and Wet-bulb thermostats controlled respectively by the dry-bulb and wet-bulb temperatures of such air, means controlled by a dry-bulb thermostat for controlling said air-heating means, and means operated jointly by pressures developed by a dry-bulb thermostat and a Wet-bulb thermostat acting in opposition for controllin the humidifying eficct of said air-humiditying means.

u 1,315, 17 i H H. In combination, air-heating means, air-humidifying meanssaid air-heating and said air-humidifying means being arranged to. act on a common body of air, dry-bulb and wet-bulb thermostats controlled respectivelyby the dry-bulb and wet-bulb temperatures of such air, means controlled by a dry-bulb thermostat for controlling said airheating means, and means operated join'tlv by pressures developed by a dry-bulb thermostat and awet-bulb thermostat for con respectively by a dry-bulb thermostat and a wet-bulb thermostat and tending respec-' tively to increase and to decrease the humidifying effect of said air-humidifying means.

16. In combination, air-humidifying means, a dry-bulb thermostat and a wet-bulb thermostat responsive respectively to the dry-bulb temperature and to the wet-bulb temperature of the air on which said humidifyiug means acts. and means operated jointly by pressures developed by said drybulb thermostat and said wet-bulb thermostat acting in opposition for controllin the humidifying effect of said air-humiditying means.

17. In combination, ant humldlfyingf means, a dry-bulb thermostat and a wet-bulb thermostat responsive respectively to the dry-bulb temperature and to the wet-bulb temperature of the air on which said humidifying means acts. and means operated jointly by pressures developed by said drybulb thermostat and said wet-bulb thermostat for controlling the humidit'ying effect of said air-humidifying means.

18. In combination, air-humidifying means, a dry-bulb thermostat and a wet-bulb thermostat responsive respectively to the dry-bulb temperature and to the wet-bulb temperature of the air on which said humidifying means acts, and two devices controlled respectively by said dry-bulb thermostat and said wet-bulb thermostat and tending respectively to increase anddecrease the humidifying effect of said air-'hmnidifying means.

19. In combination, a water-containing vessel exposed to air to be humidified, means for heating the water insaid vessel, a dry bulb therl'nostat and a \vet'bulb thermostat responsive respectively to the dry-bulb and wet-bulb temperatures of the air to which means controlled jointly by said dry-bulb thermostat and said wet-bulb thermostat acting in opposition for controlling the supply ofhea-t to said water-heating means. 20; In combination, a water-containing vessel exposed to air to be humidified, means forheating the water in said vessel, a drybulb thermostat and a wet-bulb thermostat responsive respectively to the dry-bulb and wet-bulb temperatures of the air to which said water-containing vessel is exposed, and means controlled jointly by said dry-bulb thermostat and said wet-bulb thermostat for controlling the supply of heat to said waterheating means.

21. In combination, a water-containing vessel exposed to air to be humidified, means for heating the water in said vessel, :1 drybulb thermostat and a wet-bulb thermostat responsive respectively to the dry-bulb and wet-bulb temperatures of the air to which said water-containing vessel is exposed, and two devices controlled respectively by said dry-bulb thermostat and said wet-bulb thermostat and tending respectively to increase and to decrease the supply of heat to said water-heating means.

22. In combination, a valve for controlling the flow of fluid, a dry-bulb theremostat and a wet-bulb thermostat responsive respectively to the dry-bulb temperature and the wet-bulb temperature of a body of air, and means operated jointly by pressures developed by said two thermostats acting in opposition for controlling said'valve.

In combination, a valve for controlling the flow of fluid, a dry-bulb thermostat and a wet-bulb thermostat responsive respectively to the dry-bulb temperature and the wet-bulb temperature of a body of air, and means operated jointly by pressures developed by said two thermostats for controlling said valve.

24. In combination, a valve for controlling the flow of fluid, a dry-bulb thermostat and a wet-bulb thermostat responsive res )c-ct-ively to the dry-bulb temperature and tie wetbulb temperature of a body of air, and two devices controlled respectively by said dry-bulb thermostat and said'wet-bulb thermostat and tending respectively to open and close said valve.

25. In combination, a water-containing vessel exposed to air to be humidified, means for heating the water in said vessel, a drybulb thermostat and'a wet-bulb thermostat responsive respectively to the dry-bulb and wet-bulb temperatures of the air to which said water-containing vessel isexposed, and means operated jointly by pressures developed by .said dry-bulb thermostat and said wet-bulb thermostat acting in opposition for controlling the supply of heat to said water-containing vessel is exposed, and

means -operated jointlybry pressures developedby said dry-bulb thermostat and said vWet-bulb thermostat for controlling the supply of heat to said water-heating means. 27. In combination, a humidificationcontrolling member, a dry-bulb fluid-pressure thermostat and a wet-bulb fluid pres.

sure thermostat responsive respectively to the dry-bulb and wet-bulb temperatures'of A a body of air, and meansoperated jointly by the fiuidspressures developed by said two thermostats acting in opposition for controlling said member,

28. In combination, a humidification-controlling member, a dry-bulb fluid-pressure thermostat and a wet-bulb fluid pressure thermostat responsive respectively to the dry-bulb and wet-bulb temperatures of a body of air, and means operated jointly by the fluid-pressures developed by said two thermostats for controlling said member.

29. In combination, a humidifioation-controlling member, a dry-bulb uid-pressure thermostat and a wet-bulb uid pressure thermostat responsive respectively to the dry-bulb and wet-bulb temperatures of a body of air, and two devices responsive to the fluid pressure developed by said two thermostats respectively, and tending respectively to operate said member to increase and' decrease the humidification.

In witness whereof, I have hereunto set my hand at Indianapolis, Indiana, this 7th day of January, A. D. one thousand nine hundred and nineteen.

ARTHUR E. KRI-OK. 

